1. Field of the Invention
The invention relates to a method of fabricating a pixel structure and a method of fabricating an organic light emitting device.
2. Description of Related Art
An organic light emitting device is a self-luminous device. Generally, an active organic light emitting device includes a plurality of pixel structures, and the pixel structure includes a thin-film transistor, an anode electrically connected to the thin-film transistor, a light-emitting layer and a cathode. The thin-film transistor includes a gate electrode, a source, a drain and a channel layer.
A material of the channel layer of the thin-film transistor is generally amorphous silicon (a-Si). Generally, to reduce a contact resistance between the channel layer and the source or between the channel layer and the drain, an ohmic contact layer is generally formed on the channel layer. However, since a carrier mobility of the a-Si thin-film transistor is low and reliability thereof is poor, a metal oxide semiconductor thin-film transistor is developed.
A material of a source and a drain of the metal oxide semiconductor thin-film transistor is generally aluminium or molybdenum. However, an etchant (aluminium acid) used for etching aluminium or molybdenum does not have a high etching selectivity for a metal oxide semiconductor channel layer of the metal oxide semiconductor thin-film transistor, so that it is hard to control an etching process of the source and the drain of the metal oxide semiconductor thin-film transistor.
Moreover, according to a general fabrication process of the organic light emitting device, a thin-film transistor is first formed, and then a first organic layer is formed to cover the thin-film transistor, and a second organic layer is further formed to serve as a stop barrier of the light emitting layer of the organic light emitting device. Since such method requires two fabrication processes of the organic layers, a fabrication cost thereof is relatively high.